Waldenström's macroglobulinemia (WM) is a distinct clinicopathological entity resulting from the accumulation, predominantly in the bone marrow, of clonally related lymphoplasmacytic cells which secrete a monoclonal IgM protein. This condition is considered to correspond to lymphoplasmacytic lymphoma (LPL) as defined by the World Health Organization classification system. WM is a rare disorder, with fewer than 1,500 cases occurring in the United States annually. There is a 2- to 3-fold risk increase of developing WM in people with a personal history of autoimmune diseases with autoantibodies and particularly elevated risks associated with hepatitis, human immunodeficiency virus, and rickettsiosis (Arch. Intern. Med., 2008, 168(17), 1903-9). There is no single accepted treatment for WM, and there can be a marked variation in clinical outcome. Objective response rates are high (>80%) but complete response rates are low (0-15%) (Clin. Adv. Hematol. Oncol., 2009, 7(10), 677-81, 687-90). Thus, there is a need for effective treatment of WM.